NVD / CVE Program· CNA GitHub_M

CVE-2021-21349: A Server-Side Forgery Request can be activated unmarshalling with XStream to access data streams from an arbitrary URL referencing a resource in an intranet or…

HighCVSS 8.6 · v3.1—Proof of concept Fix available

Noroxi assessment

Priority: Plan (action score 48/100)

Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
Probability of exploitation in the next 30 days: 46.8% (FIRST EPSS); higher than 98.8% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: libxstream-java (Debian:12) 1.4.15-2; libxstream-java (Debian:9) 1.4.11.1-1+deb9u2; com.thoughtworks.xstream:xstream (Maven) 1.4.16.
Severity is disputed: the assigning authority (CNA) scores it 6.1, NVD 8.6.
Mentioned 3 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Add it to your regular patch cycle. Upgrade to libxstream-java (Debian:12) 1.4.15-2; libxstream-java (Debian:9) 1.4.11.1-1+deb9u2; com.thoughtworks.xstream:xstream (Maven) 1.4.16 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker to request data from internal resources that are not publicly available only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.

Published: Mar 23, 2021
Updated: Oct 7, 2026
EPSS: 46.8% · 98th percentile
CWE: CWE-502

Report tools

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Action score

Plan

Add it to your regular patch cycle.

CVSS: 34 / 40 · 8.6 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 14 / 30 · 46.8%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 8.6
CNA · GitHub_M: 6.1; 2.5 point gap

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
Proof of concept exists, no weaponized module
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
xstream	xstream	cpe:2.3:a:xstream:xstream
netapp	oncommand insight	cpe:2.3:a:netapp:oncommand_insight
apache	activemq	cpe:2.3:a:apache:activemq
apache	jmeter	cpe:2.3:a:apache:jmeter
debian	debian linux	cpe:2.3:o:debian:debian_linux
fedoraproject	fedora	cpe:2.3:o:fedoraproject:fedora
oracle	banking enterprise default management	cpe:2.3:a:oracle:banking_enterprise_default_management
oracle	banking platform	cpe:2.3:a:oracle:banking_platform
oracle	banking virtual account management	cpe:2.3:a:oracle:banking_virtual_account_management
oracle	business activity monitoring	cpe:2.3:a:oracle:business_activity_monitoring
oracle	communications billing and revenue management elastic charging engine	cpe:2.3:a:oracle:communications_billing_and_revenue_management_elastic_charging_engine
oracle	communications policy management	cpe:2.3:a:oracle:communications_policy_management

and 5 more

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

x-stream xstream
- < 1.4.16affected

Affected versions · NVD (20)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

apache activemqbefore 5.15.14
apache activemq5.16.0
apache activemq5.16.1
apache jmeterbefore 5.5
debian debian linux10.0
debian debian linux11.0
debian debian linux9.0
fedoraproject fedora33
fedoraproject fedora34
fedoraproject fedora35
netapp oncommand insightall versions
oracle banking enterprise default management2.10.0
oracle banking enterprise default management2.12.0
oracle banking platform2.12.0
oracle banking platform2.4.0
oracle banking platform2.7.1
oracle banking platform2.9.0
oracle banking virtual account management14.2.0
oracle banking virtual account management14.3.0
oracle banking virtual account management14.5.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	libxstream-java	before 1.4.15-2	1.4.15-2
Debian:9	libxstream-java	before 1.4.11.1-1+deb9u2	1.4.11.1-1+deb9u2
Maven	com.thoughtworks.xstream:xstream	before 1.4.16	1.4.16
openSUSE:Leap 15.2	xstream	before 1.4.16-lp152.2.6.1	1.4.16-lp152.2.6.1
openSUSE:Leap 15.3	xstream	before 1.4.16-3.8.1	1.4.16-3.8.1
openSUSE:Tumbleweed	xstream	before 1.4.18-1.1	1.4.18-1.1
SUSE:Linux Enterprise Module for Development Tools 15 SP2	xstream	before 1.4.16-3.8.1	1.4.16-3.8.1

Same product

xstream: all records

Other highest-scoring records for the same primary product.

CVE-2021-39144XStream is vulnerable to a Remote Command Execution attackKEV
93Now
CVE-2019-10173It was found that xstream API version 1.4.10 before 1.4.11 introduced a regression for a previous deserialization flaw.
68This week
CVE-2013-7285Xstream API versions up to 1.4.6 and version 1.4.10, if the security framework has not been initialized, may allow a remote attacker to run…
64This week

Published before and after this one in the same product

← EarlierCVE-2021-21347Mar 23, 2021 · XStream is vulnerable to an Arbitrary Code Execution attack
43Plan
← EarlierCVE-2021-21348Mar 23, 2021 · XStream is vulnerable to an attack using Regular Expression for a Denial of Service (ReDos)
34Monitor
Later →CVE-2021-21350Mar 23, 2021 · XStream is vulnerable to an Arbitrary Code Execution attack
44Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
debian:libxstream-java	1.4.15-2 · Debian:12	Package registry (OSV)
Maven:com.thoughtworks.xstream:xstream	1.4.16	Package registry (OSV)
opensuse:xstream	1.4.16-lp152.2.6.1 · openSUSE:Leap 15.2	Package registry (OSV)
suse:xstream	1.4.16-3.8.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP2	Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Proof-of-concept repository on GitHub	stars:1	2021-05-09

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedMar 23, 2021
First PoCMay 9, 2021+47 d
TodayNov 12, 2026+2061 d

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-22-0247 · Mar 24, 2022(RedHat Güvenlik Güncellemesi)
TR-21-0989 · Dec 13, 2021(IBM Güvenlik Bildirimi)
TR-21-0674 · Aug 25, 2021(IBM Güvenlik Bülteni Yayınladı)

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: none
Availability: none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Changed
Confidentiality impact: High
Integrity impact: None
Availability impact: None

Weakness class (CWE)

CWE-502 · Deserialization of Untrusted Data

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

nvd-primary

Root cause

Data received over the network is deserialized into the language’s native object format without verifying its source. Code paths inside the object can be triggered during deserialization.

The bug in code

The whole CWE-502 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

python

1payload = sock.recv(65536)
2job = pickle.loads(payload)

Fixed

python

1payload = sock.recv(65536)
2if not hmac.compare_digest(sign(payload), header_sig):
3    raise PermissionError("invalid signature")
4job = JobSchema.validate(json.loads(payload))

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

Object InjectionCAPEC-586likelihood: Medium · High

ATT&CK techniques

—

Change log (2)

SSVC exploitation— → noneOct 7, 2026, 8:07 PM UTC
Fix✗ → ✓Sep 28, 2026, 10:47 PM UTC

For records you follow, these changes also arrive as notifications. →

References

x-stream.github.io/changes.html#1.4.16

Show all references (13 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records